1. Field of the Invention
This invention relates to a method of producing fuel oil from cellulosic materials, especially from cellulosic garbage by a catalytic hydrogenation performed on a derivative of the garbage.
2. Description of the Prior Art
For over 50 years attempts have been made to find a commercially viable method for making fuel oil by catalytically hydrogenating coal or similar carbonaceous materials. Generally the coal is hydrogenated in the presence of cheap expendable catalysts such as metals (including metal compounds) of Group 8 of the first transition period namely iron, cobalt and nickel or of Group 6A namely chromium, molybdenum and tungsten or of the first period of mid-transition metals namely vanadium,, chromium and manganese or certain amphoteric metals, namely zinc and aluminium. In practice in order to achieve commercially acceptable yields, the conventional hydrogenations have been performed at temperatures above the critical temperature of water (i.e. 374.degree. C.) and at pressures above 100 atmospheres which is usually regarded as the maximum pressure safely containable within a welded vessel. For example, U.S. Pat. No. 2,115,336 (issued in 1938) teaches the hydrogenation of Jura shale oil using a catalyst comprising molybdenum and aluminium compounds at temperatures of from 450.degree. to 500.degree. C. and pressures of above 200 atmospheres. Carbon monoxide rapidly poisons the cheap expendable catalysts listed above and so the gas could not be tolerated in the hydrogen used in the conventional hydrogenation of coal. However, U.S. Pat. No. 3,694,342 teaches that the hydrogenation of coal using hydrogen containing some carbon monoxide can be performed using for example catalysts comprising a metal of Group 8 of the first transition period, i.e. iron, cobalt and nickel provided the hydrogenation is performed in a hydrogen donor solvent and provided steam is introduced into the reaction zone "to offset the deactivation tendencies of carbon monoxide." The carbon monoxide is "offset" by the occurrence of the water gas shift reaction, i.e. EQU CO+H.sub.2 O.fwdarw.CO.sub.2 +H.sub.2
In short the essence of the teaching of U.S. Pat. No. 3,694,342 is to remove poisonous carbon monoxide from the reaction by converting it to harmless carbon dioxide.